Method of curing concrete



Patented lune 5, 1928.

ROBERT B. GAGE, OF TRENTQN, NEW JERSEY.

METHOD or CURING CONCRETE.

Ho Drawing.

The strength of a mass of concrete is dependent upon the even drying,setting and aging of the mass. This is diflicult to rightly accomplishedin the manufacture of 1 5 concrete roads and pavements because of therelatively large surface exposed to the dry-. ing action of the airand-sun which tends to dry the surface before the even hydration of thecement has occurred.

To overcome this the surface of a concrete road after it has been placedis sometimes covered with water by building an earth dam on each side ofthe concrete and across it at intervals. .This is quite costly, and notvery practical 'when the pavement is constructed on a grade. Othermethods of ouring concrete are straw onburlap, and to keep thesematerials wetted by sprinkling until the curing of the troublesome notonly because of the necessity of frequent sprinkling, but also becauseit is necessary to prevent the covering from being disturbed by thewind. Burlap or canvas v have also been suspended on frames a shortdistance above the pavement, but; this is a costly method and the framesare diflicult to keep in place in windy weather.

I have discovered that a more efficient and more economical method ofaccomplishing the even drying and setting of concrete is to cover thesurface of the concrete after it has been'placed, with a layer ofbituminous felt or other heavy paper saturated or coated with awaterproof bituminous layer. Ordinary roofing felt answers the purposewell.

This material, difier'ing from those previously used for the purpose, iswaterproof, so that the sun and air acting upon the upper surface of thecovering do not draw up an evaporate the moisture of the upper surface.

of the concrete; but, on the contrary, the moisture is retained beneaththe bituminous felt so that the upper surface of the concrete is keptmoist and consequently cured at a Application filed August 15, 1925.Serial No. 50,483.

to cover the surface with concrete has been accomplished, but this isdmaintaining such covering until the concrete surface is completely andevenly set.

rate more nearly corresponding to that of the lower part of the concretewhich is in contact with the damp ground. Furthermore bituminous felt ishighly absorbent of heat and the warmth of the subjacent concrete thuscreated helps the even hardening of the concrete, and also preventsfreezing on frosty nights. At the end of a few days the curing isaccomplished and the covering is removed.

I am aware that various absorbent coverings have been employed toprotect the surface of freshly laid.concrete from the cold and toprevent it from freezing. I am also aware of the use of various dampenedsurfaces as I have above described to prevent the too rapid drying ofthe upper surface of the concrete by the atmosphere and the sun.

My invention differs from these in thatI employ as a temporary coveringa felt paper which has been rendered waterproof or nonabsorbent ofwater, by the application of a bituminous saturation orcoating. Ibelieve this to be novel, and I have found that it is highly efficientfor the reasons which I have 7 previously explained.

Having thus described my invention, I claim:

1. The method of curing concrete which consists in placing the concreteand then temporarily covering the surface thereof which is exposed tothe atmosphere with a non-absorbent bituminous felt, untilthe evencuring of the concrete is accomplished.

2. The method ofmaking a concrete pavement which consists in placing alayer of concrete upon a' suitable foundation; and temporarily coveringthe uppersurface thereof with a'layerof bituminous felt, and

In testimony whereof, I have hereunto signed my name at Trenton, NewJersey, this 6th day of August, 1925. u

' ROBERT'B. GAGE.

